Near field RFID system with multiple reader coils
A near field RFID system includes an RFID reader and an RFID tag. The RFID reader includes a transmit path and a receive path, wherein the transmit path includes: an encoding section coupled to convert data into encoded data; a digital to analog conversion module coupled to convert the encoded data into an analog encoded signal; a power amplifier coupled to amplify the analog encoded signal; and a plurality of coils coupled to generate a plurality of electromagnetic fields from the analog encoded signal. The RFID tag that includes: a coil coupled to generate a current and a recovered signal from at least one of the plurality of electromagnetic fields; a power recovery circuit coupled to generate a voltage from the current; and a data processing section coupled to process the recovered signal, wherein the data processing section is powered via the voltage.
1. An apparatus, comprising:
a first near field device including:
an encoding section for encoding data thereby generating encoded data;
a digital to analog conversion module for processing the encoded data thereby generating an analog encoded signal;
a plurality of coils for:
producing a first electromagnetic field in accordance with transmitting the analog encoded signal; and
producing a second electromagnetic field in accordance with receiving a response signal from a second near field device;
a response signal section for processing the response signal corresponding to the second electromagnetic field; and
a transmit blocking circuit for blocking energy of the first electromagnetic field associated with the analog encoded signal from interfering with the processing of the response signal.
2. The apparatus of claim 1 , wherein:
the response signal section including a digitization module for processing the response signal thereby generating a digital signal; and
at least one of a pre-decode module and a decode module for processing the digital signal.
3. The apparatus of claim 1 , further comprising:
a coil controller, coupled to the plurality of coils, for operating the plurality of coils in accordance with an electromagnetic field cancellation avoidance scheme.
4. The apparatus of claim 3 , wherein the electromagnetic field cancellation avoidance scheme comprising at least one of:
frequency diversity; and
time diversity.
5. The apparatus of claim 1 , wherein:
the plurality of coils being a plurality of traces on a plurality of layers of an integrated circuit.
6. The apparatus of claim 1 , wherein the second near field device including:
a coil for producing at least one additional electromagnetic field in accordance with receiving a signal corresponding to the analog encoded signal or transmitting the response signal to the first near field device; and
system parameters for selectively operating the coil for a near field RFID communication and for a far field RFID communication.
7. The apparatus of claim 1 , wherein:
the first near field device being one of a plurality of radio frequency identification (RFID) readers within an RFID system; and
the second near field device being one of a plurality of RFID tags within the RFID system.
8. The apparatus of claim 7 , wherein:
the RFID system including a computer or server communicatively coupled to the plurality of RFID readers, for at least one of processing first data received from the plurality of RFID readers and providing second data to the plurality of RFID readers.
9. The apparatus of claim 1 , wherein the first near field device including:
a protocol processing module for:
processing the response signal after having undergone processing by the response signal section; and
providing the data to the encoding section for encoding.
10. The apparatus of claim 1 , wherein:
the first near field device being an radio frequency identification (RFID) reader; and
the second near field device being an RFID tag.
11. The apparatus of claim 1 , wherein:
the first near field device being implemented using a first integrated circuit including the encoding section, the digital to analog conversion module, the response signal section, and the transmit blocking circuit;
the plurality of coils being implemented off-chip with respect to the first integrated circuit; and
the second near field device being implemented within a second integrated circuit.
12. An apparatus, comprising:
a first near field device including:
an encoding section for encoding data thereby generating encoded data;
a digital to analog conversion module for processing the encoded data thereby generating an analog encoded signal;
a plurality of coils for:
producing a first electromagnetic field in accordance with transmitting the analog encoded signal; and
producing a second electromagnetic field in accordance with receiving a response signal;
a response signal section for processing the response signal corresponding to the second electromagnetic field; and
a transmit blocking circuit for blocking energy of the first electromagnetic field associated with the analog encoded signal from interfering with the processing of the response signal; and
a second near field device including:
a coil for producing a third electromagnetic field in accordance with receiving the analog encoded signal and for providing a recovered signal there from;
a data processing section for processing the recovered signal thereby generating the response signal; and wherein:
the coil producing a fourth electromagnetic field in accordance with transmitting the response signal to the first near field device.
13. The apparatus of claim 12 , wherein the first near field device including:
a coil controller, coupled to the plurality of coils, for operating the plurality of coils in accordance with an electromagnetic field cancellation avoidance scheme.
14. The apparatus of claim 13 , wherein the electromagnetic field cancellation avoidance scheme comprising at least one of:
frequency diversity; and
time diversity.
15. The apparatus of claim 12 , wherein:
the first near field device being one of a plurality of radio frequency identification (RFID) readers within an RFID system; and
the second near field device being one of a plurality of RFID tags within the RFID system.
16. The apparatus of claim 15 , wherein:
the RFID system including a computer or server communicatively coupled to the plurality of RFID readers, for at least one of processing first data received from the plurality of RFID readers and providing second data to the plurality of RFID readers.
17. A method for operating a near field device, the method comprising:
encoding data thereby generating encoded data;
processing the encoded data in accordance with digital to analog conversion thereby generating an analog encoded signal;
operating a plurality of coils for:
producing a first electromagnetic field in accordance with transmitting the analog encoded signal; and
producing a second electromagnetic field in accordance with receiving a response signal from at least one additional near field device;
processing the response signal corresponding to the second electromagnetic field; and
blocking energy of the first electromagnetic field associated with the analog encoded signal from interfering with the processing of the response signal.
18. The method of claim 17 , further comprising:
operating the plurality of coils in accordance with an electromagnetic field cancellation avoidance scheme.
19. The method of claim 18 , wherein the electromagnetic field cancellation avoidance scheme comprising at least one of:
frequency diversity; and
time diversity.
20. The method of claim 17 , wherein:
the first near field device being an radio frequency identification (RFID) reader; and
the second near field device being an RFID tag.